There is a device known in the related art that drives an electromagnetic proportional valve in correspondence to the operation amount of an electric lever and applies pilot pressure generated thereby to a control valve so as to drive a hydraulic actuator (refer to, for example, patent reference literature 1). In the device disclosed in Patent Reference Literature 1, pilot pressure applied to the control valve is detected by a pressure sensor. The device calculates control pressure in correspondence to the operation amount of the electric lever and compares the detected pressure with the control pressure so as to make a decision as to an abnormality in the electromagnetic proportional valve. If it is decided that an abnormality has occurred in the electromagnetic proportional valve, the device stops driving the hydraulic actuator.
Patent Reference Literature 1: Japanese Laid Open Patent Publication No. H7-19207